Particle Strength of Calcareous Sand in Nansha Islands, South China Sea

Single particle strength is the main factor that influences particle breakage. In order to explore particle strength characteristics and the relationship between the strength and size of calcareous sand from the South China Sea, single particle crushing tests were conducted using self-made test equipment. Hundreds of particles (0.72-3.12 mm) divided into three groups of different sizes were used to perform the test. The results show that the strength characteristics of the particles were similar to those of a typical brittle material and were lower than that of quartz sand. Under flat unconfined compression, two types of uniaxial compressive force-displacement curves were defined according to the tests, related to the shape and structure of the calcareous sand particles. Statistical data analysis shows that the calcareous sand particles' strength is in good agreement with the Weibull distribution. The particle crushing strength decreases as the particle diameter increases. Different shapes of calcareous sand particles show different strength characteristics. In addition, the mineral composition, microstructure, distribution of inner voids and fracture are related to the particle strength of calcareous sand.